The recovery of copper by smelting has been the practice in the industry for a long time but more recently copper ores, residues, and other metal sources have also been subjected to solvent (or liquid-liquid) extraction methods for recovery of the metals. The ore, for example, is leached with sulfuric acid and the dissolved metal ions are transferred to an organic phase containing extraction reagents or extractants. This organic solution is also called the solvent in hydrometallurgy. The extractants that are now used are not very selective for copper over iron, the latter being a major contaminent in copper ore.
A number of reagents have been used to extract copper and other metals from aqueous solutions. The one most closely related to that of this invention is 1,4,8,11-tetrathiacyclotetradecane (TT14C4) used in combination with organophilic anions introduced to the metal in an aqueous phase. The metal is then transferred to the organic extractant phase with the anions as a salt; however, this method is not practical because of the expense of the organophilic anions. Therefore, there is a need to provide a process for removing copper and silver and other metals from one and other metal sources that is selective, simple, inexpensive and efficient.